Method of manufacturing a semiconductor device

ABSTRACT

The invention aims to provide substrate treatment equipment that can automatically collect a substrate in a normal condition without needing manual operation. The equipment includes a substrate holder  26  for holding substrates  12  in a multistage manner and a substrate transfer unit  34  for transferring the substrates  12  into the substrate holder  26 , wherein a substrate holding condition of the substrate holder  26  is sensed by a sensing section  60 . The sensing section  60  has photo-sensors  64   a,    64   b , and sensing waveforms sensed by the photo-sensors  64   a,    64   b  are compared with a normal waveform. A control section  66  is provided, which controls a substrate transfer unit  34  such that substrates  12  other than at least a substrate  12  that was determined to be abnormal are transferred by the unit.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a Divisional of application Ser. No. 10/570,156 filed Mar. 27,2006, which in turn is a National Phase Application of PCT/JP2004/013791filed Sep. 22, 2004. This application claims the benefit of JapanesePatent Application No. JP 2003-333664, filed Sep. 25, 2003. The entiredisclosures of the prior applications are hereby incorporated byreference herein in its entirety.

BACKGROUND

The invention relates to substrate treatment equipment for treating asubstrate of a semiconductor device or the like, and a manufacturingmethod of the substrate.

As is generally known, there is equipment as this type of substratetreatment equipment, which has a substrate holder for holding substratesin a multistage manner and a transfer unit for transferring thesubstrates into the substrate holder, and treats the substrates in atreatment furnace while holding a number of substrates in the substrateholder.

SUMMARY

When the substrates are heated in the treatment furnace, or removed fromthe treatment furnace and then cooled, abnormal phenomena such as cracksor warps may occur in the substrates due to thermal stress. When thecracks or warps are in such a level that they result in disablingautomatic carrying of the substrates by an automatic substrate carryingmechanism, tweezers for taking in and out the substrates may collidewith the substrates, and push down the substrate holder, leading to aserious accident such as damage of a quartz component.

To solve this, a mechanism for sensing a condition of the substrates canbe considered to be provided. For example, the sensing mechanism has aphoto-sensor provided on the transfer unit, and senses the substrates inthe substrate holder by moving the photo-sensor using a vertical shaftof the transfer unit.

Portions where light is intercepted by the substrates and portions wherelight is transmitted between the substrates are recorded, and a shiftlevel of the vertical shaft and sensing data of the photo-sensor areused to find whether a substrate pitch is normal with respect to a pitchof the substrate holder which has been known.

When a substrate drops from a support slot on the support holder due tocracking of the substrate or transfer errors, discrepancy may occurbetween interception/transmission data of light by the photo-sensor andthe recorded data, and a substrate on a support slot at which thediscrepancy appeared is determined to be in an abnormal transfercondition.

Moreover, when the substrate completely drops from a support slot andconsequently the substrate does not lie on the support slot on which thesubstrate is essentially to be held, since light is not intercepted, thesubstrate can be sensed as a lost substrate.

After a substrate condition is sensed by the substrate sensingmechanism, a substrate that has been transferred onto the support slotat which an error occurred is manually collected by an operator who hasentered the equipment.

Furthermore, after the substrate has been visually confirmed to be safe,it is automatically transferred by the automatic substrate carryingmechanism.

Currently, it is an issue to realize a mini-environment by using an L/Ldevice (load/lock device), a N₂ purge device, and an organic filter andthe like in order to avoid entering of moisture or particles containedin the air and thus reduce contamination of the substrate in substratetreatment equipment. When an abnormal substrate is manually collectedafter an abnormal phenomenon is sensed by the substrate conditionsensing mechanism as describe above, particles generated from a humanbody may have adverse effects on a substrate in a normal condition athigh possibility. In substrate treatment equipment using the N₂ purgedevice, an atmosphere within the equipment must be returned to the airto reset the environment such that the operator can enter the equipment.In such a situation, a natural oxidation film on a surface of thesubstrate can not be reduced, consequently a substrate that has beennormally transferred also has a problem in process.

An object of the invention is to provide substrate treatment equipmentthat can automatically collect a substrate in a normal condition withoutneeding manual operation.

To solve the problem, a first feature of the invention is substratetreatment equipment having a substrate treatment chamber, a substrateholder that can be inserted into the substrate treatment chamber andholds substrates in a multistage manner in a substantially verticaldirection, a substrate transfer unit for transferring the substratesonto the substrate holder, and a sensing device for sensing a holdingcondition of the substrate held in the substrate holder; which includesa control device that, in transfer of the substrates, senses the holdingcondition of the substrates using the sensing device, and controls thesubstrate transfer unit such that substrates other than a substratewhich was determined to be in an abnormal substrate holding conditionare transferred by the substrate transfer unit.

A second feature of the invention is substrate treatment equipmenthaving a substrate treatment chamber, a substrate holder that can beinserted into the substrate treatment chamber and holds substrates in amultistage manner in a substantially vertical direction, a substratetransfer unit for transferring the substrates onto the substrate holder,and a sensing device for sensing a holding condition of the substrateheld in the substrate holder; which includes a control device that, intransfer of the substrates, senses the holding condition of thesubstrates using the sensing device, and controls the substrate transferunit such that substrates other than a substrate which was determined tobe in an abnormal substrate holding condition are transferred by thesubstrate transfer unit; wherein the control device controls thesubstrate transfer unit such that substrates other than the substratedetermined to be abnormal and at least one of substrates held on andunder the substrate determined to be abnormal are transferred by thesubstrate transfer unit.

A third feature of the invention is a manufacturing method of asubstrate having a step of inserting a substrate holder in whichsubstrates are held in a multistage manner in a substantially verticaldirection into a substrate treatment chamber, a step of performing heattreatment to the substrates in the substrate treatment chamber, a stepof sensing a holding condition of the substrates held in the substrateholder, and a step of transferring substrates other than a substratethat was determined to be in an abnormal substrate holding condition bya substrate transfer unit.

A fourth feature of the invention is a manufacturing method of asubstrate having a step of inserting a substrate holder in whichsubstrates are held in a multistage manner in a substantially verticaldirection into a substrate treatment chamber, a step of performing heattreatment to the substrates in the substrate treatment chamber, a stepof sensing a holding condition of the substrates held in the substrateholder, and a step of transferring substrates other than a substratethat was determined to be in an abnormal substrate holding condition bya substrate transfer unit; wherein the substrates are transferred insuch a manner that substrates are carried for each of severalpredetermined number of substrates, and when all the predeterminednumber of substrates to be carried are determined to be in a normalsubstrate holding condition, all the predetermined number of substratesare carried together, and when at least one of the substrates isdetermined to be in an abnormal substrate holding condition, substratesother than the substrate that was determined to be abnormal in thepredetermined number of substrates are carried one at a time.

While control means may control the transfer unit such that all thesubstrates other than the substrate that was determined to be abnormalare transferred by the transfer unit, it preferably controls thetransfer unit such that substrates other than the substrate that wasdetermined to be abnormal and at least one of substrates on and underthe substrate are transferred by the transfer unit.

According to the substrate treatment equipment of the invention, intransfer of substrates, the holding condition of the substrates issensed, and the transfer unit is controlled such that substrates otherthan at least a substrate that was determined to be abnormal aretransferred by the transfer unit, therefore substrates in a normalcondition can be automatically collected, and entering of particles intothe equipment or oxidation on the substrates can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view generally showing substrate treatmentequipment according to an embodiment of the invention;

FIG. 2 is a cross section view generally showing the substrate treatmentequipment according to the embodiment of the invention;

FIG. 3 is a cross section view showing a treatment furnace used in thesubstrate treatment equipment according to the embodiment of theinvention and the periphery of the furnace;

FIG. 4 is a side view showing a substrate transfer unit used in thesubstrate treatment equipment according to the embodiment of theinvention;

FIG. 5 is a side view showing a substrate holder used in the substratetreatment equipment according to the embodiment of the invention;

FIG. 6 is views for illustrating an abnormal condition of substrateholding in the substrate treatment equipment according to the embodimentof the invention, wherein (a) is a plane view showing a normalcondition, (b) is a front view showing a condition of cracking in asubstrate, (c) is a front view showing the substrate holder, and (d) isa side view of the substrate holder;

FIG. 7 is views for illustrating a sensing method when an abnormalcondition of substrate holding is found in the substrate treatmentequipment according to the embodiment of the invention, wherein (a) isan illustrative view showing a relation between the abnormal conditionof substrate holding and a sensing waveform, and (b) is a plane view ofthe substrate transfer unit; and

FIG. 8 is a flowchart showing operation of substrate sensing in thesubstrate treatment equipment according to the embodiment of theinvention.

DETAILED DESCRIPTION OF EMBODIMENTS

Next, an embodiment of the invention is described according to drawings.

FIG. 1 and FIG. 2 show substrate treatment equipment 10 according to theembodiment of the invention. The substrate treatment equipment 10 isvertical-type one for performing diffusion treatment or CVD treatment toa substrate. In the substrate treatment equipment 10, a load/unloadstage 18 for inserting a pod 14 accommodating substrates 12 formed fromsilicon and the like from the outside into a housing 16 is fixed on afront face of the housing 16. A cassette shelf 22 for storing theinserted pod 14 is provided within the housing 16. Moreover, an N₂ purgechamber 24 is provided within the housing 16. The N₂ purge chamber 24acts as a carrying area of the substrates 12, or a space for carrying inand out a substrate holder (boat) 26. When treatment of the substrate 12is performed, the N₂ purge chamber 24 is filled with inert gas such asN₂ gas to prevent a natural oxidation film from being formed on thesubstrate 12.

FOUP is used for the pod 14, and the substrate 12 can be carried whilebeing isolated from the air by covering an opening provided in a sideface of the pod 14 by a cap (not shown), and the substrate 12 can betaken in and out into/from the pod 14 by removing the cap. For example,25 substrates 12 are stored in the pod 14. A pod opener 28 is providedin a front face of the N₂ purge chamber 24 so that the cap of the pod 14is removed to communicate the atmosphere within the pod 14 with theatmosphere within the N₂ purge chamber 24. The pod 14 is carried amongthe pod opener 28, cassette shelf 22 and load/unload stage 18 by thecassette transfer unit 30. Air cleaned by a clean unit (not shown)provided on the housing 16 is flowed through a space for carrying thepod 14 by the cassette transfer unit 30.

Within the N₂ purge chamber 24, a substrate holder 26 for loading aplurality of substrates 12 in a multistage manner, a substrate alignmentdevice 32 for aligning a notch (or an orientation flat) of the substrate12 to an optional position, and a substrate transfer unit 34 forcarrying the substrate 12 between the pod 14 on the pod opener 28 andthe substrate alignment device 32 are provided. A treatment furnace 36for treating the substrates 12 is provided in an upper part of the N₂purge chamber 24, and the substrate holder 26 is loaded into thetreatment furnace 36 by a boat elevator 38 as elevating means, orunloaded from the treatment furnace 36 by it. The treatment furnace 36has a furnace port which is closed by a furnace port shutter 40 duringexcept for a period during treating the substrate 12.

Next, operation of the substrate processing equipment 10 according tothe embodiment is described.

First, the pod 14 carried from the outside of the housing 16 by AGV orOHT is set on the load/unload stage 18. The pod 14 set on theload/unload stage 18 is directly carried onto the pod opener 28, orstocked temporarily on the cassette shelf 22 and then carried onto thepod opener 28 by the cassette transfer unit 30. When the pod 14 iscarried onto the pod opener 28, the cap of the pod 14 is removed by thepod opener 28, and thereby the atmosphere within the pod 14 iscommunicated with the atmosphere within the N₂ purge chamber 24.

Then, a substrate 12 is removed from the pod 14 in a condition of beingcommunicated with the atmosphere within the N₂ purge chamber 24 by thesubstrate transfer unit 34. The removed substrate 12 is aligned by thesubstrate alignment device 32 such that the notch or the orientationflat is fixed in an optional position, and after that carried onto thesubstrate holder 26.

When the substrates 12 have been carried into the substrate holder 26,the furnace port shutter 40 of the treatment furnace 36 is opened, andthen the substrate holder 26 having the substrates 12 mounted therein isloaded into the treatment furnace 36 by the boat elevator 38.

After loading, predetermined treatment is performed to the substrates 12in the treatment furnace 36, and after the treatment, the substrates 12and the pod 14 are ejected to the outside of the housing 16 in thereverse order of the above procedure.

FIG. 3 shows a peripheral configuration of the treatment furnace 36. Thetreatment furnace 36 has an outer tube 42 formed from a heat resistantmaterial such as quartz (SiO₂). The outer tube 42 is in a cylindricalshape that is closed at an upper end and has an opening at a lower end.An inner tube 44 is disposed concentrically within the outer tube 42. Aheater 46 as heating means is disposed concentrically on the outercircumference of the outer tube 42. The heater 46 is held on the housing16 via a heater base 48.

As shown in FIG. 4 and FIG. 5, in the substrate holder 26, for example,three poles 50 formed from, quartz, silicon carbide and the like aredisposed parallel in a vertical direction, and the substrates 12 areheld by support slots 52 formed on the poles 50. The substrate transferunit 34 has a transfer unit body 54 that moves vertically and rotates,and a main tweezers body 56 that moves reciprocally on the transfer unitbody 54. For example, four tweezers 58 a, 58 b, 58 c and 58 d are fixedto the main tweezers body 56 in a manner of extending parallel to oneanother. Moreover, sub tweezers body 57 is provided on the transfer unitbody 54 such that it can reciprocally move either along with orindependently of the main tweezers body 56. Tweezers 58 e are fixed tothe sub tweezers body 57 at a position below the four tweezers 58 ato 58d and parallel to them. Therefore, as shown in FIG. 4, the substratetransfer unit 34 can collectively transfer five substrates 12 using thefive tweezers 58 a to 58 e, and can transfer one monitor substrate(sheet transfer) using the tweezers 58 e at the lowermost stage. Whenthe monitor substrate is transferred, as shown in FIG. 5, a spacecorresponding to one slot is opened between sets of collectivelytransferred, five substrates 12, and a monitor substrate 59 is extractedfrom a pod different from a pod for typical substrates 12, and insertedbetween the sets of the five substrates.

For example, 25 substrates 12 are accommodated in the pod 14, and in thecase that the substrates 12 are transferred into or collected from thesubstrate holder 26 by the substrate transfer unit 34, when there is noabnormal substrate in five slots (slot group), five substrates 12 arecollectively transferred or collected using the five tweezers 58 a to 58e, and when there is an abnormal substrate in the slot group, onlynormal substrates are collected using the tweezers 58 e at the lowermoststage. The monitor substrate may be collected one at a time as ininsertion.

A sensing section 60 as sensing means is provided on the transfer unitbody 54. The sensing section 60 has parallel, two arms 62 a, 62 b, andis provided such that the arms 62 a, 62 b can be turned on a side faceof the transfer body 54. Near front ends of the arms 62 a, 62 b,transmission-type photo-sensors 64 a, 64 b are provided, and one of thephoto-sensors is a light emitting element, and the other is a lightreceiving element. When a holding condition of the substrates 12transferred into the substrate holder 26 is sensed, the arms 62 a, 62 bare turned and fixed to a side of the substrate holder 26 so that lightaxes of the photo-sensors 64 a, 64 b run through the substrates 12, andthen sensing output of the photo-sensors 64 a, 64 b is monitored whilethe substrate transfer unit 34 is moved from a lower end to an upper endof the substrate holder 26. On the other hand, when the substrates 12are transferred into the substrate holder 26 by the substrate transferunit 34, the arms 62 a, 62 b are turned to a side opposite to thesubstrate holder side to prevent the arms 62 a, 62 b from beinginterfered with the substrates 12 or the substrate holder 26.

As shown in FIG. 3, analog signals outputted from the photo-sensors 64a, 64 b are outputted to a control section 66 including a computer. Thecontrol section 66 controls the substrate transfer unit 34 via a driversection 68 such as a motor.

Next, sensing of the abnormal condition of the substrates 12 isdescribed.

As shown in FIG. 6( a), it is assumed that the light emitting element 64a is situated at the right side, and the light receiving element 64 b issituated at the left side in a view from a top of the substrate holder26, and the light emitting element 64 a and the light receiving element64 b are disposed at a front face side of the substrate holder 26. Asshown in FIG. 6( b), the substrate 12 may crack while being held in thesubstrate holder 26 or drop from the support slot 52 of the substrateholder 26, resulting in falling into abnormal condition. As shown inFIG. 6( c) and FIG. 6( d), the abnormal conditions of the substrate 12are given as follows.

A. drop/in pairs

B. drop/light-emitting side drop (left face drop)

C. drop/light-receiving side drop (right face drop)

D. drop/rear drop (back face drop)

E. drop/front drop (front face drop)

F. cracking/center cracking

G. cracking/front cracking

H. cracking/rear cracking

J. no substrate

A substrate 12, which is in the normal condition, is supported parallelto a support slot 52.

FIG. 7( a) shows a relation of signal output from the photo-sensors 64a, 64 b to the abnormal condition. A positional relation between thesubstrate holder 26 and the photo-sensors 64 a, 64 b is assumed that thephoto-sensors 64 a, 64 b are at a front side, and a side opposed to thephoto-sensors is a back side as shown in FIG. 7( b).

When the holding condition of the substrates 12 is normal, waveformsoutputted from the photo-sensors 64 a, 64 b are regular. For example,when a left or right surface of the substrate 12 drops, sensingwaveforms of the photo-sensors 64 a, 64 b are gradually spread at leftand right of a peak compared with a normal waveform, consequently widthat a reference line is increased. When the substrate 12 completely dropsfrom the support slot 52, sensing output of the photo-sensors 64 a, 64 bdisappears at that support slot 52 from which the substrate has dropped.When the substrate 12 drops from the support slot 52 at the back, thepeak is shifted to the upper side compared with the normal waveform.When the substrate 12 drops from the support slot 52 at the front, thepeak is shifted to the lower side compared with the normal waveform. Thecase that the substrate 12 has cracked can be also sensed.

FIG. 8 shows an example of substrate sensing operation by the controlsection in a flowchart.

First, in step S10, drive of the substrate transfer unit and thephoto-sensors is started. That is, as previously shown in FIG. 3, thearms 62 a, 62 b are rotationally fixed to the side of the substrateholder 26, and then a transfer condition of the substrates 12 is sensedby the photo-sensors 64 a, 64 b while the substrate transfer unit 34 israised from the lowermost end of the substrate holder 26 at a constantspeed. The quantity of light of light emitting/receiving of thephoto-sensors 64 a, 64 b is inputted into the control section 66 asanalog signals.

In next step S12, the analog signals inputted from the photo-sensors 64a, 64 b are converted into digital signals to analyze detection outputfrom the photo-sensors 64 a, 64 b. In this analysis of output from thephoto-sensors 64 a, 64 b, the sensing waveforms from the photo-sensors64 a, 64 b are recorded and then compared with the normal waveform sothat an abnormal slot is specified and thus an abnormal slot list isprepared.

In next step S14, whether before or after heat treatment is determined.When determination is made as before heat treatment, the operation isadvanced to step 16 to determine whether an abnormal slot is found ornot, and when it is determined that the abnormal slot is not found, theoperation is advanced to step S18 in which the substrate supporter 26 iscarried into the treatment furnace 36, and then heat treatment iscarried out. On the other hand, when determination is made as after heattreatment in the step S14, or when it is determined in the step S16 thatthe abnormal slot is found, the operation is advanced to step S20 inwhich collection of the substrates 12 is started. As described before,the collection of the substrates 12 is performed for each of slotgroups, and it is begun at a first slot group and ended at a fifth slotgroup that is a final slot group. In next step S22, whether all the fivesubstrates in the slot group to be collected are transferred in thenormal condition (not found in the abnormal slot list) is determined.When all the five substrates are determined to be in the normalcondition in the step S22, the operation is advanced to step S24 inwhich all the five substrates are collected together. On the other hand,when it is determined that there is a substrate in the abnormalcondition in the five substrates 12 in an objective slot group (found inthe abnormal slot list) in the step S22, the operation is advanced tostep S26 in which only the substrates in the normal condition arecollected in a manner of sheet transfer. When collection is notcompleted for all the slot groups in the step S28, the operation isreturned to processing for a next slot group, and when collection iscompleted for all the slot groups, the operation is finished.

In the embodiment, when a substrate in the abnormal condition is found,the substrate in the abnormal condition is remained in the substrateholder, and all the substrates in the normal condition are returned intothe pod, however, the invention is not necessarily limited to this. Whenthe substrate in the abnormal condition is found, a substrate on orunder the substrate may receive a kind of damage. Thus, it is alsoacceptable that at least one of substrates on and under the substrate inthe abnormal condition is also remained in the substrate holder, andother substrates in the normal condition are returned into the pod.

INDUSTRIAL APPLICABILITY

The invention can be used for substrate treatment equipment thatautomatically collects substrates.

1. A manufacturing method of a semiconductor device, comprising:inserting a substrate holder on which substrates are held in amultistage manner in a substantially vertical direction into a substratetreatment chamber, performing heat treatment to the substrates in thesubstrate treatment chamber, sensing a holding condition of thesubstrates held in the substrate holder, and transferring substratesother than a substrate determined to be abnormal and at least one of thesubstrates contacting the substrate determined to be abnormal in thesubstrate holder by a substrate transfer unit, wherein in transferringsubstrates, when all of a predetermined number of substrates to becarried are determined to be normal in the substrate holder, all of thepredetermined number of substrates are carried together, and when atleast one of the predetermined number of substrates is determined to beabnormal in the substrate holder, substrates other than the substratedetermined to be abnormal in the predetermined number of substrates andthe at least one of the substrates contacting the substrate determinedto be abnormal in the substrate holder are carried one at a time.
 2. Amanufacturing method of a semiconductor device comprising: inserting asubstrate holder on which substrates are held in a multistage manner ina substantially vertical direction into a substrate treatment chamber,performing heat treatment to the substrates in the substrate treatmentchamber, sensing a holding condition of the substrates held in thesubstrate holder, and transferring substrates by a substrate transferunit, wherein when all of a predetermined number of substrates to becarried are determined to be normal in the substrate holder, all of thepredetermined number of substrates are carried together, and when atleast one of the predetermined number of substrates is determined to beabnormal in the substrate holder, substrates other than the substratedetermined to be abnormal in the predetermined number of substrates arecarried one at a time.
 3. A transferring method of a substratecomprising: inserting a substrate holder on which substrates are held ina multistage manner in a substantially vertical direction into asubstrate treatment chamber, performing heat treatment to the substratesin the substrate treatment chamber, sensing a holding condition of thesubstrates held in the substrate holder, and transferring substratesother than a substrate determined to be abnormal and at least one of thesubstrates contacting the substrate determined to be abnormal in thesubstrate holder by a substrate transfer unit, wherein in transferringsubstrates, when all of a predetermined number of substrates to becarried are determined to be normal in the substrate holder, all of thepredetermined number of substrates are carried together, and when atleast one of the predetermined number of substrates is determined to beabnormal in the substrate holder, substrates other than the substratedetermined to be abnormal in the predetermined number of substrates andthe at least one of the substrates contacting the substrate determinedto be abnormal in the substrate holder are carried one at a time.